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Page 1
Production Facility
2000 Tall Pines, Largo, FL 33771
Installation Pocket Guide
Head Quarters & Sales
272 Duchaine Blvd., New Bedford, MA 02745
800-757-6996
Fax 508-998-1447
www.alliedeg.com
MC Tuff, Mc Lite, AC-90, AC-Lite, HCF-90, HCF-Lite, and Kaf-Tech, and Tyco are
trademarks or registered trademarks of Tyco and/or its affiliates in the United States and in other countries.
All other brand names, product names, or trademarks belong to their respective owners.
2000KT-0610
2.5M
AFC’S T YPE MC & AC CABLES — FEATURING THE RAINBOW ID SYSTEM
MC
AC
KT pocket guide cvr spred2006
• Proper Installation methods for
Type MC and Type AC
• NEC References
• Illustrated details
AC MC
KT pocket guide cvr spred2006
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5:35 PM
Page 3
Cable Color ID System
Cable Color ID System
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Page 1
Armored cable (Type AC) and metal clad cable
(Type MC) are increasingly becoming the wiring solution
of choice for engineers, contractors and building owners
across America.
AC & MC Cables
SECTION 1
Introduction to Type AC and Type MC cables including
the differences between these two products. Identifies
important references from the National Electrical Code.®
SECTION 2
Explanation of the proper techniques for installing
AC and MC cable including cutting and derating.
The title National Electrical Code® and NEC® are trademarks
registered to the National Fire Protection Association.
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Page 2
SECTION 1
Armored (Type AC) Cable Construction
Introduction to AC & MC Cables
Armored cable (Type AC) and metal clad cable
(Type MC) provide a fast and efficient way of wiring
both new construction and remodeling work. Their flexible
metal armor provides mechanical protection of the electrical
conductors while enabling them to bend around corners.
The cables are pre-wired at the factory eliminating the need
to pull conductors into a raceway, which in turn greatly
reduces the possibility of conductor damage during pulling.
The National Electrical Code has accepted AC and MC
cables for decades, with statistics showing that they have an
excellent fire safety record.
Because AC & MC cable can be fished for long distances,
it is quick and easy to install. It’s own weight can carry it
between partitions and it can be run without concern for its
contact with pipes or other obstructions.
Wire pullers, fish ropes or tapes, dispensers and lubricants
are eliminated. AC & MC cable does the job in less space,
with fewer bending restrictions and less cutting and
connecting than most other wiring products.
Armored cable (Type AC) and Metal Clad cable
(Type MC) have a flexible metal armor of similar outward
appearance, but that is where the similarity ends. There are
major differences in construction and uses permitted.
2
As described by the National Electrical Code
NEC® 2002 Article 320, armored cable Type AC is
a “fabricated assembly of insulated conductors in a
flexible metallic enclosure.”
Type AC cable is manufactured to UL Standard 4.
It consists of 2 to 4 copper conductors in sizes 14 AWG
to 1 AWG inside an interlocked metal armor of steel or
aluminum construction. Type AC cable can have no
more than four insulated conductors plus a grounding
conductor (for a total of 5 conductors only) and cannot
be manufactured larger than 1 AWG per UL 4.
A 16 AWG aluminum bonding wire is inside of, and
in physical contact with, the metal armor providing a
low-impedance fault-return path required for the operation
of overcurrent protection devices. The bonding wire is
unique to AC cable and allows the outer metal armor
in conjunction with the bonding wire to be used as an
equipment ground.
It is important to remember that the bare bond wire is
not an equipment grounding conductor. It is the bond wire
that, in combination with the interlocked metal armor,
provides a low impedance equipment grounding path.
Each of the copper conductors is covered with a
thermoplastic insulation (THHN with a 90°C rating)
and are individually wrapped in a moisture resistant,
fire retardant paper.
According to NEC Article 320.40, an insulated (antishort) bushing is required when installing Type AC cable.
It is installed at the time of termination and designed to
protect the conductors from damage. Kaf-Tech provides
bushings in bags packaged with the cable.
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AC
AC
AC-90® and AC Lite®
Armored Cables
Type AC Cable - Uses Permitted
The uses permitted for AC cable are governed by NEC
Article 320 and any applicable local codes.
AC-90 ® and AC-Lite ® are
manufactured with a black
armor for easy identification
of cable type.
Additional color bands
identify circuit/phase
conductor colors.
• Where not subject to physical damage for branch circuits and
feeders in both exposed and concealed work and in cable trays
where identified for such use
• In dry locations and embedded in plaster finish on brick or
other masonry, except in damp or wet locations
• Run or fished in the air voids of masonry block or tile walls
where the walls are not exposed or subject to excessive moisture
or dampness
• Under raised floors, above suspended ceilings and in other
environmental air-handling spaces per NEC 300.22(C)
Galvanized Steel Armor
(Color-Coded Black)
Insulated
Bushing
Bare Aluminum
Bonding Strip
Copper Conductors
Paper Wrap
(Each Conductor)
AC-90
Nylon
Thermoplastic
THHN Insulation
®
• In both exposed and concealed work
• In dry locations
• Embedded in plaster finish or brick or other masonry, except
in damp or wet locations
• To be run or fished in the air voids of masonry block or tile
walls where such walls are not exposed or subject to excessive
moisture or dampness
• FPN: The “uses permitted” is not an all-inclusive list
Type AC Cable - Uses NOT Permitted
Aluminum Interlocked Armor
(Color-Coded Black)
Insulated
Bushing
Bare Aluminum
Bonding Strip
Copper Conductors
According to NEC Article 320.12, AC cable can not be
installed in the following locations:
• Where subject to physical damage
• In damp or wet locations
Paper Wrap
(Each Conductor)
AC-Lite®
Nylon
Thermoplastic
THHN Insulation
• In air voids of masonry block or tiles where such walls are
exposed or subject to excessive moisture or dampness
• Where exposed to corrosive fumes or vapors
• Embedded in plaster finish on brick or other masonry in
damp or wet locations
4
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AC
AC
Health Care Facilities Cable
HCF-90 ® and HCF-Lite ®
are manufactured with a
green armor for easy
identification of cable type.
Additional color bands
identify circuit/phase
conductor colors.
Galvanized Steel Armor
(Color-Coded Green)
Insulated
Bushing
Bare Aluminum
Bonding Strip
Copper Conductors
Copper Ground
Paper Wrap
(Each Conductor)
Nylon
Thermoplastic
THHN Insulation
HCF-90 ®
Aluminum Interlocked Armor
(Color-Coded Green)
Insulated
Bushing
Bare Aluminum
Bonding Strip
Copper Conductors
Copper Ground
Paper Wrap
(Each Conductor)
HCF-Lite ®
Nylon
Thermoplastic
THHN Insulation
Type AC cable is available in standard AC,
AC-Lite® (aluminum) or Health Care Facilities Cable
(Kaf-Tech’s HCF-90® and its aluminum version HCF-Lite®).
HCF, or hospital grade cable, is constructed in the same
manner as standard AC cable, but with the addition of a
green grounding conductor.
Kaf-Tech’s HCF-90 ® and HCF-Lite® Health Care
Facilities Cable
This additional ground allows HCF to be used in patient
care areas of health care facilities (other than hazardous
locations) including hospitals, nursing homes, dental offices,
outpatient facilities and medical centers per NEC 517.13.
The separate green grounding conductor satisfies the
requirement of Article 517.13(A) that:
“Wiring Method: All branch circuits serving patient care
areas shall be provided with a ground path for fault current
by installation in a metal raceway system, or a cable having a
metallic armor or sheath assembly. The metal raceway
system, or metallic cable armor, or sheath assembly shall
itself qualify as an equipment grounding return both in
accordance with 250.118.”
HCF Cables satisfy:
NEC 517.13(B) . . .
“The grounding terminals of all recepticals and all noncurrent carrying conductive surfaces of fixed electric
equipment likely to become energized that are subject to
personal contact operating at over 100 volts, shall be
grounded by an insulated copper conductor. The equipment
grounding conductor shall be sized in accordance with Table
250.122 and installed in metal raceways or as part of listed
cables having a metallic armor or sheath assembly with the
branch-circuit conductors supplying these receptacles or
fixed equipment.”
(NOTE: HCF cables may not be used on emergency circuits in a health care setting
except as noted 517.303(C)(C).
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Page 8
MC
MC
Metal Clad (Type MC) Cable Construction
MC TUFF® and MC-Lite®
Metal Clad Cables
Kaf-Tech manufactures
its lightweight steel
MC TUFF™ cable with a
blue armor for easy
identification of cable type.
Additional color bands
identify circuit/phase
conductor colors.
Galvanized Steel Armor
(Color-Coded Blue)
Assembly Tape
Copper
Conductors
Copper
Ground
MC TUFF ®
Nylon
Thermoplastic
THHN Insulation
As described by NEC Article 330, Metal Clad Type MC
cable is a “factory assembly of one or more insulated circuit
conductors with or without optical fiber members enclosed
in an armor of interlocking metal tape or a smooth or
corrugated metallic sheath.”
Type MC cable is manufactured to UL Standard 1569.
MC cables have 2 or more solid or stranded conductors
in sizes 18 AWG and larger. The number of conductors
allowed in an MC cable is not restricted by UL. The
conductors may be of copper, aluminum or copper-clad
aluminum.
The metal armor may be a smooth tube, a
corrugated tube, or an interlocked metal armor.
Kaf-Tech manufactures MC cable with interlocked
metal armor and copper conductors.
The make-up of Kaf-Tech’s 600 volt interlocked
armor MC cable consists of:
• Copper circuit and grounding conductors
covered with thermoplastic insulation
• An overall polypropylene cable assembly tape
• An outer galvanized steel or aluminum
interlocked armor
Unlike Type AC cable, the armor of interlocked Type MC
cable is not an equipment grounding means and Type MC
cable requires a bare or green grounding conductor.
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Page 10
MC
Type MC Cable - Uses Permitted
The uses permitted for MC cable are governed by NEC
Article 330 and any applicable local codes.
Uses Permitted For MC Cable
Let’s review the major differences between
AC and MC cables.
• Where not subject to physical damage for services,
feeders and branch circuits
• For power, lighting, control, and signal circuits
TYPE AC CABLE
TYPE MC CABLE
NUMBER OF
CONDUCTORS
Limited to a maximum
of 4 conductors plus a
grounding conductor.
Not limited to the
number of conductors.
SIZE OF
CONDUCTORS
14 AWG to 1 AWG
18 AWG or larger
GROUNDING
Contains a 16 AWG bond
wire in constant contact
with the metal armor
allowing the armor and
bond wire combination
to be used as an
equipment ground.
Does not contain a
bonding wire and the
armor is not an
equipment ground, but
supplements the
internal grounding
conductor equaling
one grounding path.
CONDUCTOR
WRAPPING
Individual conductors are
wrapped in a moisture
resistant, fire retardant
paper.
Individual conductors
are not wrapped in
paper but do have an
overall polypropylene
assembly tape.
• Indoors, exposed or concealed
• Direct buried where identified for such use
• Under raised floors, above suspended ceilings and in
other environmental air-handling spaces per NEC
300.22(C)
• Outdoors or in wet locations where the armor has an
overall outer, moisture resistant PVC jacket
• In places of assembly
• In cable tray or raceway or as open runs
• In locations classified as hazardous as permitted in NEC
Articles 501, 502, 503, 504, and 505
• As aerial cable on a messenger
10
Along with these differences in construction, there are also
differences in the uses permitted for these cables as discussed
in the previous pages.
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Page 12
SECTION 2
For example, according to NEC Table 310.16, a cable with
three 12 AWG copper, 90°C THHN insulated conductors is
rated at 30 amperes.
Project Planning
Project planning is an important step in the installation of
any wiring method. Proper planning will enable a safe and
efficient cable installation.
Circuit planning is developed from the plans and
specifications produced by the design engineer. The project
estimator and project manager plan the circuits and cable runs
to meet the design requirements in a safe and efficient manner.
The final “as-built” drawings are developed and submitted to
the building owner reflecting the actual field installation of
the electrical circuitry. An important component of circuit
planning is ampacity and cable derating.
Cable Ampacity and Derating
The ampacity of a cable is the maximum amount of
current it can carry in a given situation without exceeding its
temperature rating. Most AC & MC cables have a
temperature rating of 90°C.
AC or MC Cable With Three Or Less Current
Carrying Conductors
The amperage rating of an AC or MC cable containing
three current carrying conductors or less can be found in
Table 310.16 of the NEC. These values are based on an
ambient temperature of 30°C (86°F). You must use the
correction factors at the bottom of the Table 310.16 for
other ambient temperatures.
12
In the above example, if the ambient temperature is 38°C
rather than 30°C, the correction factor of .91 found at the
bottom of the table is used to derate the conductors by 91%.
This is done by multiplying the .91 by the 30 amperes for a
resulting ampacity of 27.3 amperes.
If there is a * beside the AWG size then you must refer to
the fine print note at the bottom of the page which directs
you to NEC Section 240.4(D). This section explains the
over-current protection required for certain wire gauge sizes
and ampacities.
AC or MC Cable With More Than Three Current
Carrying Conductors
When utilizing a multi-conductor cable assembly of more
than three current carrying conductors, the conductors must
be derated. To derate the cable, use the adjustment factors in
NEC Table 310.15(B)(2)(a). If harmonic loads exist, the
neutral conductors must also be considered to be “current
carrying” and included in the derating process. Again, refer to
NEC section 240.4(D) for AWG sizes with a * beside them.
For example, a 12 AWG cable with 4-6 conductors has an
available ampacity of 30, but per Table 310.15(B)(2)(a) must
be reduced to 80% (multiplied by .80) leaving the available
ampacity at 24. See sample calculation in Figure 1.
When 7 to 9 conductors are used in a raceway or cable, per
Table 310.15(B)(2)(a), the table value of ampacity must be
reduced by a 0.70 multiplier. Refer to Table 310.15(B)(2)(a)
for quantities greater than 9 conductors.
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Figure 1
Armored Cable Derating Example
90°C RATED ARMORED CABLE 12 AWG
WITH 4 COPPER CONDUCTORS.
1) Find conductor ampacity in NEC Table 310.16
- 12AWG, 90°C = 30 amperes
2) Find adjustment factor in NEC Article 310.15(B)(2)(a).
- 30 x .80 = 24 amperes
Cutting AC & MC Cable
Type AC and MC cable should be cut with an armored
cable rotary cutter. Rotary cutters have many advantages
over other methods. Nicking and cutting of the conductors
is eliminated and the cuts can be made quickly and safely.
Bundled 12 AWG Type AC or MC Cables
Where multi-conductor cables are stacked or bundled for
more than 24 inches, without maintaining spacing, the
conductors must be derated except that the ampacity of 12
AWG Type AC and MC cables are not adjusted according to
Table 310.15(B)(2)(a). The derating of bundled 12 AWG
AC and MC cables is determined by Exception No. 5 to
NEC Section 310.15(B)(2).
Double Derating
When installing an MC cable consisting of more than
three current-carrying conductors in an area where the
ambient temperature is other than 30°C (86°F), the
correction factors at the bottom of NEC Table 310.16
are used with the adjustment factors in NEC Article
310.15(B)(2)(a). This is considered double derating of
the cable.
For example, a 12 AWG cable with five 90°C insulated
conductors is run through an ambient temperature
of 105°F. Using the adjustment factors in NEC Article
310.15(B)(2)(a), each conductor must be derated 80% of
the ampacity of 30 amperes taken from Table 310.16. An
additional derating of 87% must also be applied using the
correction factors at the bottom of Table 310.16 to account
for the high ambient temperature. Thus, the resulting
ampacity is limited to 20.88 amperes per conductor.
14
An armored cable rotary cutter.
Instructions For Use:
1) Place the cable in the tool and tighten the tool
to the armor.
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Page 16
The first step in the rough-in phase is to determine the
number of home run circuits and from where the wiring will
originate. Once this is done, time should be taken to
determine the best and shortest routes for each cable run.
Long runs of spider web type routing not only require more
cable but increase voltage drop. This is very important to
consider when locating boxes for receptacles, lights and
switches. If long runs are required, oversizing the circuit
conductors is recommended to limit voltage drop.
2) Rotate the handle a couple of brisk turns.
AC & MC cable is available on reels and in coils. If using
a reel, simply draw the cable from the end of the reel. If
using a coil, draw the cable from the center of the coil to
prevent kinking.
3) Remove the cable from the tool, and twist the armor
to separate.
Installing AC & MC Cable
Type AC & MC cable is installed after the rough-in phase
of locating and setting all boxes and enclosures. Rough-in
occurs when all the interior and exterior walls are framed
but before the sheet rock is installed.
16
A coil of MC cable
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Bridging Cable Across Open Spaces
In general, AC and MC cable must hug the surface it is
wired over. The NEC prohibits bridging across open spaces
with the following five exceptions:
1) When the cable is fished.
2) When flexibility is required a box may be installed
near a motor or appliance using a short piece of free
AC cable up to 24 inches long, between the box and
motor or appliance.
3) Lengths of not more than 6 feet from the last point
of support for connections within an accessible
ceiling to lighting fixtures or equipment.
4) Where installed in cable trays.
5a) For Type AC cable in other than vertical runs
through holes or notches in framing members where
distance between members does not exceed 4.5 feet
and is securely fastened in place by an approved
means within 12 inches of each box, cabinet,
conduit body or other cable termination.
5b) For Type MC cable in other than vertical runs
through holes or notches in framing members where
the distance between members does not exceed 6
feet. Cables containing four or fewer conductors
sized no larger than AWG 10 must be secured
within 12 inches of each box, cabinet, fitting or
other cable termination.
Type MC Cable running through punched holes
in metal framing members.
Bending Radius
Care should be taken not to exceed the bending radius of
the cables when routing around corners. According to NEC
Article 320.24, for AC cable, the radius of the curve of the
inner edge of any bend shall not be less than 5 times the
diameter of the cable. NEC Article 330.24(B) states that for
MC Cable, the radius shall not be less than 7 times the
external diameter of the cable.
Supporting AC & MC Cables
All cable runs must be continuous from outlet to outlet.
According to NEC Article 320.30, AC cable must be
supported and secured at intervals of 4.5 feet or less
(unless routed through a framing member) and within
12 inches of every termination.
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Page 20
According to NEC Article 330.30, MC cable must be
supported and secured at intervals of 6 feet or less (unless
routed through a framing member) and cables containing
four or fewer conductors sized no larger than 10 AWG
must be secured within 12 inches of every termination.
Type MC cable secured in a
vertical cable tray
Terminating AC & MC Cables
As noted, AC and MC cable support requirements are
waived when the cable is fished. This is a major advantage
of AC and MC cable in remodeling work over other wiring
products that cannot be fished.
AC and MC cable may also be installed in cable tray, per
NEC Article 392. Cable is only required to be secured in
this installation for vertical runs.
20
When terminating or splicing at a junction, outlet
or switch box, cut the cable so that 6 inches of free
conductor is left for connections or splices. Use an
approved connector and insure a proper bond by firmly
tightening the connectors to both the box and the cable.
Please note: set screw connectors cannot be used with
aluminum armor Type AC cable.
To terminate an AC cable, insert an anti-short bushing
and bend back the exposed length of bonding wire. The
bonding wire can be bent back before or after the bushing is
inserted. There are several techniques used for this procedure
as pictured on the next page.
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Page 22
A bushing must be used
with Type AC cable.
Here is an example of
an approved connector for
AC and MC cables.
Insert the cable into the connector and secure the
connector into the box. Be sure that the anti-short bushing
is plainly visible in the connector for easy inspection. The
same procedure is followed for MC cable with the exception
that there is no bonding wire. Although anti-short bushings
are only required by the NEC for AC cable, most
manufacturers recommend their use with MC cable.
MC cable installed in a box with 6 inches of free conductors
left for connections or splices.
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NOTES
Page 24
KT pocket guide cvr spred2006
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Page 3
Cable Color ID System
Cable Color ID System
9/21/06
5:35 PM
Page 1
Production Facility
2000 Tall Pines, Largo, FL 33771
Installation Pocket Guide
Head Quarters & Sales
272 Duchaine Blvd., New Bedford, MA 02745
800-757-6996
Fax 508-998-1447
www.alliedeg.com
MC Tuff, Mc Lite, AC-90, AC-Lite, HCF-90, HCF-Lite, and Kaf-Tech, and Tyco are
trademarks or registered trademarks of Tyco and/or its affiliates in the United States and in other countries.
All other brand names, product names, or trademarks belong to their respective owners.
2000KT-0610
2.5M
AFC’S T YPE MC & AC CABLES — FEATURING THE RAINBOW ID SYSTEM
MC
AC
KT pocket guide cvr spred2006
• Proper Installation methods for
Type MC and Type AC
• NEC References
• Illustrated details
AC MC